Incandescent lamp



Sept. 15, 1959 s. c. PEEK, JR 2,904,

INCANDESCENT LAMP Filed April 26, 1957 war- 1N VEN TOR: SAND/WED C. FEE/f, JR

BY; 3 I

ATTORNE United States Patent IN CANDESCENT LAlVlP Sandford C. Peek, In, Hamilton, Mass., assignor, by mesne assignments, to Sylvania Electric Products Inc, Wilmington, Del., a corporation of Delaware Application April 26, 1957, Serial No. 655,213 Claims. c1. 315-45 This invention relates to incandescent lamps, and particularly to such lamps in which the maximumlight output is desired in a particular direction. Such a directional light output is desired, for example, in lamps dmigned for use with optical systems, for example, projection lamps, particularly those used in motion picture film printing, and scene illumination lamps for motion picture and television sets.

The light in such lamps is generally emitted from an electrically-heated metal filament, which is enclosed in a gas-filled bulb. Metal evaporates from the filament and is carried by the gas to deposit on and blacken-various parts of the bulb, including the portion of thebulb through which the main light output passes. deposit form a film which absorbs some of the light which would otherwise pass out of the bulb, and since the absorption is generally selective, the color of the emitted light is changed, thus causing a noticeable change in color rendition.

In addition, the absorption of light and other radiant energy increases bulb temperature in the blackened regions, thereby often softening the glass, which may bubble and explode under filling pressure, generally above atmospheric as the result of lamp operating temperature and the initial sealing pressure of the gas filling.

I have discovered that a chimney construction of such lamps reduces or removes blackening from critical areas of the glass envelope, essentially andoften entirely eliminating the aforementioned illumination loss, color shifting, and explosions.

I have discovered further that a quartz lens may be inserted inside the envelope of the device of the invention whereas in previous lamps, blackening of a lens so placed would have soon removed its effectiveness.

I have discovered also that the chimney raises the temperature of the gas in the immediate neighborhood of the filament and the resulting decrease in heat transfer to said gas reduces the wattage taken by the filament for a given temperature, and thus increases lamp efficie-ncy.

Other objects, features, and advantages of the invention will be apparent from the following specification, taken in connection with the accompanying drawings in which:

Fig. 1 is a front elevation of one embodiment of the invention, and Fig. 2 is a cross-section along line 22 in Fig. 1.

In Figure 1, a glass envelope 1 has a main cylindrical portion 2 which is constricted or necked-down to a smaller diameter at its ends 3, 4. Two copper thimbles 5, 6 are sealed through the bottom of lower end 3 to act as electrical contacts to, and as mechanical supports for, the lead-in wires 7, 8 which support and make electrical contact to the tungsten filament 9, which is arranged in a series of parallel coils, each end of the series being connected to support wires 10, 11, each of which is held in one of the larger-diameter lead-in wires 7, 8.

An insulating bridge 12, held to the lead-in wires 7, 8 by connecting wires 13, 14, 15, 16, carries the insert The metal 2,904,711 Patented Sept. 15, 1959 wires 17, which are twisted attheirends into circulets, for channeling wires 18, which move up or down adjusting to the contraction-expansion action in the filament 9 loops, to which said wires 18arehooked, Another bridge 19, supported at the ends of wires 10, 11 by the metal strips 21, 22 carries inserts 37 which hook directly onto the loops in filament 9. I

The glass envelope 1 and cylindrical metal collar 23 are united atseal 24 which is a seal'of the glass end 4 to the feathered metal edge of collar 23. The latter, at its uppen edge,'is ringed by annular, flat, metalflange 25, which, excepting its inner hole, is in plate to plate contact withmetal disk 26. Chimney 27 hangs, by means of paired attachments: 28,. 28, and 29, 29 from disk 26, down through flange. 25 and collar 23 into glass envelope 1.

Disk. 26', in Figure-1, bears-ten cooling fins 30, and the metal exhaust'tube. 31. A filling of gas inert with respect to the filament, for example, nitrogen at a pressure of 1000 millimeters of mercury can be used, although the invention is not limited to a particular pressure.

Light from filament 9 passes out of chimney 27 through opposing, circular, openings. 32, 33, one of which can be directed towards a reflector, not shown in Figure 1'. In Figure 1, paired attachments 34, 34 and 35, 35 position a quartz'lens 36 before one of the openings 32, 33.

One embodiment of the device of Figure 1 had the following measurements and, ratings: an over-all height of about 17" from the base of thirnblesS, 6 to the top of cooling fins 31 a. diameter of about 8" in the main portion of envelope 1, and, coincidentally, for'metal disk 26; a diameter of about 5" for metal collar 23 and the hole of flange 25; chimney. 27 dimensions of about 9" x 4%" x 2";.about 4." diameters for chimney openings 32, 33; about; 4%" diameter for quartz lens-36, a filament 9 of a standard type, rated, for 1.0 kw; usage. by. the art, but, in the devicedescribed herein, drawing about 17% less Wattage for the same light output; cooling fins 30, per.- pendicular to circular disk 28, these being about 6." long near the center ofsaid, disk, and about 4" long near the circumference, and having. a height of about 1".

In one method of constructing the device of Figure 1, a metal cap can be assembled from disk 26, flange 25, and collar 23; the latter two being welded together, for example, While flange 25 and disk 26 might be heliowelded all around their circumferences. All the said components of this metal cap can, by way of example and not by way of limitation, be made from copper which is a good heat conductor and capable of being sealed to glass.

In this method, for the purpose of aiding the cooling of the aforedescribed cap, ten copper strips can be welded perpendicular to the exterior side of disk 26 to act as cooling fins.

In this method, to put the aforedescribed metal cap onto the glass envelope 1, glass to metal Housekeeper sealing can be used; the seal corresponding to seal 24 in Figure 1. As such seals can be broken and rescaled, for a limited number of times, in a manner well known in the art, it becomes possible to separate the cap from glass envelope 1, and to reseal them, after, for example, substituting a new filament for an evaporated filament 9. In such case, the metal exhaust tube 31 permits exhausting and refilling, for example, with nitrogen filling at above atmospheric pressure.

In this method, chimney 27 can be made of four pieces of metal, for example, sheet steel, about 2025 thousandths of an inch thick, riveted together to form the holloW, open-ended, chimney section shown in Figure 1. The opposing openings in chimney 27 can be stamped or cut out before assembly, in an artisans manner; the four vertical corners of chimney 27 can be rounded. Chimney 27 can be suspended from the interior side of disk 26 as follows: four metal strips, all being about 3" long, the width of two being about half the approximate width of the other pair, can be riveted, respectively, to the four sides of chimney 27, in such manner that they extend upwards for clasping and riveting onto the brackets, e.g., copper fillets, welded to the interior side of disk 26 for the purpose of chimney suspension. In one embodiment, suspension from disk 26 was such that the four top edges of chimney 27 rest about 1" from disk 26, while the centers of openings 32, 33, and the center of filament 9 fall on a line, extending in the direction desired for optical purposes.

Many variations in chimney construction and suspension will occur to those skilled in the art. For example, the chimney instead of being suspended from the cap can be supported from the base, if desired.

In this method also, lead-in wires 7, 8 can be secured in thimbles 5, 6 by high-melting point solder. In that case, lead-in wires 7, 8 can be unsoldered and removed from the thimbles 5, 6, for the purpose of substituting a new filament 9.

The hot gas from the filament 9 carries the volatilized matter, from said filament, up through the chimney directly to the cool metal cap comprising disc 26, flange 25, and collar 23, thereby keeping it from depositing on the bulb 2.

What I claim is:

1. An incandescent lamp comprising an enclosing envelope part of which is metal and part of light-transmitting material, a gaseous filling therein, a filament therein, and a chimney therein around said filament and having an opening in the side thereof through which light can pass from said filament, said chimney conveying vapor from the filament to the relatively cool metal portion of said envelope and away from portions of said envelope which transmit the desired light output of said lamp.

2. An incandescent lamp comprising an enclosing envelope, a gaseous filling therein, a filament therein, a metal cap sealed to said envelope above said filament in register with the longitudinal axis thereof and in direct contact with the gases inside said envelope, and a chimney, supported from said cap and enclosing said filament, said chimney having an opening through which light 4 from the entire filament reaches the wall of the envelope.

3. An incandescent lamp comprising an enclosing envelope, a gaseous filling therein, a filament therein, contact pins sealed to one end of said envelope, electrical connections from said contact pins to and supporting said filament, a metal cap sealed to other end of said envelope and in register with the longitudinal axis of said filament, and a chimney inside said envelope and enclosing said filament, said chimney being supported from said cap and having an opening through which light from said entire filament reaches the wall of the envelope.

4. An incandescent lamp comprising an enclosing envelope, a gaseous filling therein, a filament therein, contact pins sealed to one end of said envelope, electrical connections from said contact pins to and supporting said filament, a metal cap sealed to one end of said envelope and in register with the longitudinal axis of said filament, a chimney inside said envelope and enclosing said filament, said chimney being supported from said cap and having an opening through which light from said filament is emitted, and a lens across said opening and attached to said chimney.

5. An incandescent lamp comprising an enclosing envelope, a gaseous filling therein, a filament therein, contact pins sealed to one end of said envelope, electrical connections from said contact pins to and supporting said filament, a metal cap sealed to one end of said envelope and in register with the longitudinal axis of said filament, a chimney inside said envelope and enclosing said filament, said chimney being supported from said cap and having an opening through which light from said filament is emitted, and cooling fins outside said envelope but in metallic thermal contact With said chimney.

References Cited in the file of this patent UNITED STATES PATENTS 1,325,254 Legg Dec. 16, 1919 1,632,578 Bahr June 14, 1927 1,982,067 Parker Nov. 27, 1934 2,190,313 Dinnick Feb. 13, 1940 2,269,845 Dailey Jan. 13, 1942 2,277,193 Wyss Mar. 24, 1942 2,413,006 Spencer Dec. 24, 1946 

